AQA · GCSE · Biology
Course version: 8461 · Version from Sept 2018
Students should be able to explain the role of the immune system in the…
Full specification wording
Human defence systems: Students should be able to explain the role of the immune system in the defence against disease.
If a pathogen gets past the non-specific defences, the immune system responds specifically to that pathogen.
Checked against the AQA 8461 specification (opens in a new tab) on .
- Point 2 of 4
- 4 key terms
Study notes
From the checked teaching notes for this specification point.
The idea
If a pathogen gets past the non-specific defences, the immune system responds specifically to that pathogen. White blood cells, mainly lymphocytes, recognise antigens on the pathogen surface. Each lymphocyte is specific to one antigen. When it binds, it divides to produce clones, some of which secrete antibodies that lock onto antigens, clumping pathogens so they can be destroyed by phagocytes. Other white blood cells, phagocytes, engulf and digest pathogens. Some lymphocytes remain as memory cells, so a second infection by the same pathogen triggers a faster, larger antibody response, often preventing illness. This is also how vaccination works. The immune response therefore destroys pathogens and provides long-lasting immunity.
What earns the marks
- White blood cells recognise antigens on the surface of pathogens.
- Lymphocytes produce antibodies that are specific to the pathogen's antigens.
- Antibodies bind to antigens, causing pathogens to clump so phagocytes can engulf them.
- Phagocytes engulf and digest pathogens by phagocytosis.
- Memory cells remain after infection and give a faster, stronger response on re-infection.
- The immune response is specific to the pathogen and can provide immunity.
Common mistakes and how to put them right
Saying antibodies kill pathogens directly.
Put it right: Antibodies bind antigens and help phagocytes destroy the pathogen.
Saying all white blood cells produce antibodies.
Put it right: Lymphocytes produce antibodies while phagocytes engulf pathogens.
Confusing antigens with antibodies.
Put it right: Antigens are on the pathogen surface and antibodies are produced by lymphocytes.
Exam tips
- Use the terms antigen, antibody, lymphocyte and phagocyte accurately.
- Explain the sequence: recognition, antibody production, clumping, engulfing, memory.
- Link memory cells to immunity and vaccination to show deeper understanding.
Try the lesson
The start of the Human defence systems: Students should be able to explain the role of the immune system in the defence against disease. lesson, made from checked teaching notes for this specification point.
Have a go first
Which type of white blood cell produces antibodies that destroy pathogens?
Listen
If a pathogen gets past the non-specific defences, the immune system responds specifically to that pathogen. White blood cells, mainly lymphocytes, recognise antigens on the pathogen surface. Each lymphocyte is specific to one antigen. When it binds, it divides to produce clones, some of which secrete antibodies that lock onto antigens, clumping pathogens so they can be destroyed by phagocytes. Other white blood cells, phagocytes, engulf and digest pathogens. Some lymphocytes remain as memory cells, so a second infection by the same pathogen triggers a faster, larger antibody response, often preventing illness. This is also how vaccination works. The immune response therefore destroys pathogens and provides long-lasting immunity. A strong answer earns marks for these points. White blood cells recognise antigens on the surface of pathogens. Lymphocytes produce antibodies that are specific to the pathogen's antigens. Antibodies bind to antigens, causing pathogens to clump so phagocytes can engulf them. Phagocytes engulf and digest pathogens by phagocytosis. A common slip: Saying antibodies kill pathogens directly. Instead, antibodies bind antigens and help phagocytes destroy the pathogen. Exam tip: Use the terms antigen, antibody, lymphocyte and phagocyte accurately.
Key words
Say what each word means before you turn the card.
Immune system
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Antigens and antibodies
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Specific defence
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Immunity and vaccination
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See every definition
- Immune system
- When a pathogen gets past the non-specific defences, this responds specifically to that pathogen and destroys it.
- Antigens and antibodies
- Antigens are on the pathogen surface, and antibodies are produced by lymphocytes and lock onto antigens.
- Specific defence
- White blood cells, mainly lymphocytes, recognise antigens on the pathogen surface, and each lymphocyte is specific to one antigen.
- Immunity and vaccination
- Memory cells remaining after infection give a faster, larger antibody response on re-infection, often preventing illness, and vaccination works in the same way.
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